The digital broadcasting provides clients with a commercial service which allows a broadcasting device to transmit the information about editing programs to be on-aired as EPG (Electronic Program Guide) data multiplexed on the broadcast wave, and the service also allows a receiver to receive the EPG data to be used in the receiver. Use of this EPG data allows displaying programs scheduled on-air on a TV screen as a program timetable, or searching through a number of programs for ones that meet specific conditions before displaying the ones hit by the search. For instance, “display only movie programs” is established as a specific condition, then movie programs are extracted and displayed on a TV screen.
The EPG data is formed of an identifier and an attribute of respective programs. The program identifier is the information for identifying a program, and is assigned uniquely to each program. The program attribute is the information indicating characteristics and content of the program, and includes a title, an on-air start time, a genre, the cast, or a detailed description of the program.
The program search function is this: viewer's designation of a program attribute as a search key prompts the program search function to search through the organized programs for ones satisfying the search key, and then to show the satisfying programs to the viewer. For instance, this function allows searching through the weekly programs for movie programs only, or for the programs where the president of the US appears.
FIG. 7 shows a block diagram illustrating structures of a conventional broadcasting device and its receiver. In FIG. 7, broadcasting device 14 includes program material memory 10 storing numerous materials of the programs scheduled on-air, and program information memory 11 storing numerous program information. Each one of the program information is formed of a program identifier and a program attribute. The program attribute includes a title, an on-air start time, a genre and so on. Multiplexer 13 multiplexes the data stored in memories 10 and 11 on the broadcast wave to be transmitted.
Receiver 29 includes decoder 21 which extracts the data multiplexed on the broadcast wave, and program data storage 23 stores program data extracted from the broadcast wave. Input section 24 receives input operation done by a user. Using a search condition entered through input section 24 as a search key, search section 25 searches storage 23 for a program satisfying the search key, and then extracts and outputs the satisfying program. Search result memory 26 stores the searched (satisfying) program output from search section 25. Output section 28 outputs the searched program and displays it to the viewer.
FIG. 8 shows a flowchart illustrating operation of the conventional receiver. Every program sent from the broadcasting device undergoes the search one by one (S801). To be more specific, parameter “i” is incremented sequentially, thereby searching program “i”. Then only the program satisfying the specific conditions is extracted (S802). The data of the program is stored in search result memory 26 (S803). The search ends after every program has undergone the search (S804). This related art is disclosed in Unexamined Japanese Patent Publication No. H09-83888.
Conventionally, the program search has been implemented by a processor placed in the receiver. In general, the memory and the processor in the receiver are not so sophisticated, so that several minutes are needed sometime for searching through all the programs for the program satisfying a specific condition. It is slow enough for a user to get a search result.